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How to change 3 Ph supply frequency?

  1. Jan 22, 2012 #1
    Hello,

    I would like to know about, How to change the 3 Phase supply frequency smoothly over a wide range(for example 1Hz - 100Hz)?

    suggest methods if any exists other than mentioned below :
    1)Not using Variable frequency drives
    2)Not using MG set

    Pl note that i want to know, how to change 3 phase supply frequency, not at the generation side.

    Thanks.
     
  2. jcsd
  3. Jan 22, 2012 #2

    NascentOxygen

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    If you are talking low power (e.g., to power an experimental design) then you could synthesize three sinusoids from DC using semiconductor circuits, where it's called a function generator. Quite possibly a stepped approximation to a true sine wave would suffice.
     
  4. Jan 22, 2012 #3
    No its not for experimental use.

    And i have clearly mentioned, that i want to know, how to change 3 phase supply frequency?
    So do u have any other options for the above question?
     
  5. Jan 22, 2012 #4

    sophiecentaur

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    See how it's done at either ends of high power AC-DC-AC power links (e.g. UK link with the French network). Or perhaps you are only concerned with relatively low powers. The actual spec would be vital to consider before making a choice.
     
  6. Jan 22, 2012 #5
    Why you talk about low power application?

    Yes, i can change 3 phase supply frequency using Motor generator set. Where generator rotor runs at Nr to obtain desired 'f'.
    But i dont want to implement it as it is a cumbersome process.

    so is there any other method to change supply frequency smoothly?
     
  7. Jan 22, 2012 #6

    NascentOxygen

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    May I ask what the industrial application is where you know of a need for this?
     
  8. Jan 22, 2012 #7

    sophiecentaur

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    You didn't make clear what power you are considering.
    I did not suggest a motor generator solution - how would you do that for a 1Hz supply? The generators would need to he MASSIVE.
    I was suggesting MAR technology. But 1Hz is an unrealistic suggestion for motors or inverters.

    You will not find a system for direct conversion. It will be necessary to go via DC, I am sure.
    You still do not specify the Power involved. Is it a secret?
     
  9. Jan 22, 2012 #8
    Firstly i would like thank you for patiently replying to my post.

    It deals with high power AC sources.

    Yes, that is what i want to perform. i.e. will i be able to convert 50hz 3 ph supply to 1Hz 3 phase supply or 51 or vary smoothly over a range?

    Yes you are right generators are massive and i dont prefer them too.

    So u say that direct conversion is not possible? or Do u have any idea about direct conversion?

    And there is no secret involved my friend and there's nothing to reveal.

    Finally it will be helpful if u can give me some more suggestions.
     
  10. Jan 22, 2012 #9

    sophiecentaur

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    What do you call "High Power" exactly?
    10kW
    1MW
    1GW
    ??

    I can't think of may applications that would require enormous powers at a few Hz. What would you do with 1MW at 1Hz?
    Inductances would need to be massive, in any AC equipment - either for generation or use.
     
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